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C. MARX.

DOUBLE SOUNDING BOARD FOR PIANOS. No. 343,644. Patented June 15, 1886.

N. PETERS. PhuwLmou-nphof. wnhmgmn, D. C.

UNITED STATES PATENT OFFICE.

CARL MARX, OF DRESDEN, SAXONY, GERMANY.

DOUBLE SOUNDlNG-BOARD FOR PIANOS.

SPECIFICATION forming part of Letters Patent No. 343,644, dated June 15,1886.

Application Iiled February 19, 1884. Serial No. 12l,352.

(No model.) Patented in Germany September 9, 18875, No. 26,728, and inEngland January 25, 1884, No. 2,111.

T0 a/ZZ whom t may concern.:

Be it known that I, CARL MARX, of the city of Dresden, in the Kingdom ofSaxony, and German Empire, have invented certain new and usefulImprovements in Double Sounding-Boards for Piano-Fortes and otherSimilar Instruments, (for which patents were granted to me in Germany,under No. 26,728, dated September 9, 1883, and in England, under No.2,111, dated January 25, 18811,) of which the following is aspecification.

My invention relates to improvements in double sounding` or sound boardsfor pianos and other similar instruments, the object of which is toproduce a more powerful continuous or prolonged tone.

I am aware that sounding-bodies or sound- .ing-boards, consisting ot' ahollow receptacle or shell in a curvilinear shape, formed by placingseveral veneers of wood one above the other, have been patented toRobert Volf, of London, by the British Patent No. 6,780, A. D. 1835; butthe construction and application of this system proved to be very im`practical, in consequence of the numerous defects in the same, and forthis reason never came into general use. It is also known to me that K.G. Zierold, ot' Leipsic, has patented in Germany, under No. 20,642, A.D. 1882, the application of the two boards placed above each other toform a double soundingbox. Zierold reduces the distance between his twoboards, so as to have the greatest space between the same to the left ofthe center of the boards, or almost entirely on the bass side of theinstrument, so that it' his system were employed for the cross stringinstruments the bass and tenor notes would be so loud in proportion tothe treble that a very bad eiiect would be produced; and even it' thisinstrument is strung on the straight-wire system a similar result mustbe produced, and for this reason the system has never come intopractical application. Zier-old further attaches his sounding-box to thelower surface of the main sound-board and applies his bridges, as usual,to the main sound-board, which is not only undurable, but so totallyimpractical that his system has never been employed to any extent.

My invention is calculated to overcome the manifold difficultiesheretofore experienced with the above-named sound-boards, and in orderto attain my object I employ double sound or sounding boards, which areconnected to or with each other in such manner that the smallersoundboard, to which the bridges are applied, is carried by the lower ormain sound-board.

Figure 1 is an elevation of the double soundboard and the frame of thepiano; Fig. 2, a section on the line a a a in Fig. 1.

B is the smaller sound or sounding board, to which the bridges A arefixed, and which said sound-board B is connected to the lower largersound-board, D, by means ofthe strips, ledges, or rods of woods C, whichsaid strips, ledges, or rods C are well glued to the upper sound-board,B, around or in immediate proximity to the edges of the same, and alsoto the lower or larger sound-board, D, which said lower or largersound-board, D, is firmly connected to the case or fraaie E ot theinstrument.

F F are the openings in the sound-board.

In consequence of the upper smaller soundboard, B, being smaller thanthe lower or larger soundboard, D, so that a space or part ofthe surfaceof' the latter remains uncovered by the said upper sound-board, B, thelower sound-board, D, participates in or is subjected t0 the samevibrations as the upper soundboard, B, so that a fuller` tone, whichcontinues much longer than can possibly be attained with ordinary soundboards, is achieved, whereby the tone emitted is agreeable to the ear,even when the player causes the hammer to strike with full force.

Having now described my said invention, what I claim, and desire tosecure by Letters Iatent, is-

In pianos and other similar musical instruments, a double sound orsounding board consisting of two parallel sound-boards, B and D, thelesser sound-board B being superposed on the under board, D, and havingthe bridges on which rest the strings, substantially as and for thepurpose described.

CARL MARX.

Vitnesses:

OTTO VOLEE, C. R. SCHMIDT.

